Rhode Island is one of eight states that joined a pledge Thursday to put 3.3 million zero-emission vehicles on the road by 2025. The pledge comes just weeks after the state installed 50 charging stations.

The pledge calls for more infrastructure to support the millions of electric cars expected to hit the road in the next dozen years. Every car maker is working to have an electric car for sale by 2015, but auto dealers say charging stations are key to getting consumers behind the wheel.